Twig templating engine can be used for WordPress development with the plugin called Timber. You can write simple, neat and clean code which is modular and easier to maintain. How? Simple! Keep the view part of your code separate from its data or logic.
If you are interested in learning how you can use Timber with WordPress and want a kick-start instead of going through the documentation and testing, I have written a four part series about this topic at Tuts+.